Mandrel for high-speed reeling



Aug. 5, 1969 E. D. NYSTRAND ET AL MANDREL FOR HIGH-SPEED REELING Filed Feb. 2o. 1967 United States Patent O Mice U.S. Cl. 242-685 4 Claims ABSTRACT OF THE DISCLOSURE A reeling mandrel capable of high-speed rotation without excessive vibration constructed of material having a modulus of elasticity-density ratio in excess of about 2 108 inches, as exemplified by beryllium.

The inventive mandrel finds particular utility in connection with a web-winding machine such as is shown in the co-owned U.S. Patent No. 2,769,600. A later coowned patent which also deals with a winding machine and one capable of higherspeed operation is No. 2,995,- 314 and reference to these two patents may be had for overall details of construction of the related apparatus.

In the winding of reeling of Webs, particularly tissue webs used for toilet paper, the development has been toward higher and higher speeds. With currently available equipment, severe vibration -is encountered at speeds much lower than 3000 feet per minute. With speeds of this order, contemporary mandrels vibrate at a critical frequency which can result in destruction, misoperation, etc. The object of the invention, therefore,is to provide a mandrel structure which overcomes this critical limitation.

The invention is described in conjunction with an illustrative embodiment inthe accompanying drawing, in which:

FIG. 1 is a fragmentary longitudinal section view of the inventive mandrel;

FIG. 2 is an enlarged fragmentary sectional view of the portion designated 2 on FIG. l; and

FIG. 3 is also an enlarged fragmentary sectional view of the remaining portion of FIG. 1.

In the illustration given, the numeral designates generally the inventive mandrel which is seen to be an elongated body which is supported for rotation on bearings 11, 12 and 13.

In the illustration given, the bearings 11 and 12 are what might be considered permanent bearings or lixed bearings positively installed relative to the mandrel 10.v While the bearing 13 is a releasable bearing-openable to permit the withdrawal of web material wound on the mandrel 10. All of the foregoing can be seen in detail in the previously-mentioned 'Patent No. 2,769,600.

The inventive mandrel is equipped with an end plug 14, advantageously constructed of steel which is inserted or ensleeved as at 15 within a tubular member constructed of beryllium. Thus, the bearing 13 operates against the steel end plug 14. In similar fashion, the end plug 17 adjacent the driven end of the mandrel 10 is constructed of steel and is likewise connected to the beryllium portion 16 as by ensleeving. The end plug 17 additionally is equipped with an opening 18 for purpose of accommodating a core-lock mechanism such as is described in the copending, co-owned application of Kenneth I. Gerrits, Ser. No. 571,832, tiled Aug. 11, 1966, now Patent 3,331,565.

By constructing the major portion of the mandrel length of beryllium, we achieve a construction which has a much higher frequency of vibration. The frequency of vibration is a function of the modulus of elasticity of the v 3,459,388 Patented Aug. 5, 1969 mandrel material E, mornenntof inertia I, length L and weight W as set forth inthe expressionimmediately below: f.....=f (LrEfLW) which is expressed more exactly as:

k furie N W Heretofore, mandrels have been constructed of steel, i.e., iron, and it will be noted from the table below that irrespective of changing the material of construction to lighter weight material such as magnesium or aluminum, the ratio of modulus of elasticity to density remains about constant. On the other hand, beryllium has a ratio, considerably higher and with this the problem of excessive vibration is avoided.

TABLE Elastic modulus Density (lu/ina) (1u/m3) 42X10 28. 5)(103 6. 5)(104i 10X10E Elastic modulus Material +density (inches) In the illustration given, it is seen that the major p0rtion of the length of the mandrel 10 is, constructed of beryllium and although shown as a hollow cylindrical tube, these physical parameters may be varied considerably. For example, the body portion 16 may be solid or hollow, it may be other than cylindrical and it maybe constructed of a material other than beryllium so long as it exceeds the modulus of elasticity-density ratio-of about 2 108 inches. 'i

In the particular illustration given, the overall length of the mandrel seen in FIG. 1 is 9915/1'(;`th`e portion 16 constructed of beryllium tubing being S31/2' with an internal diameter of 1.125. The location of the opening 18 for the core-lock mechanism (not shown) is 16" from the drive end of the Imandrel 10. The wall thickness of the portion 16 is 0.375". f

To illustrate the advantages accruing from the use of beryllium, for example, in comparison to steel, we set down the following calculations:

Critical frequencies of mandrels Conditions:

Uniform round tube Clamped one end-simply 'supported one end lst critical frequency:

f i' El 1 L2 W 2nd critical frequency:

156 EI f2s-*7.2* vr I=Moment of inertia of cross section (inches)4 L=Length (inches) W=Weight inch of length) E=Modulus of elasticity (#/inches2) For steel mandrels 1:0.0491 (D4-d4) (inches)4 D=Outside diameter (inches) d=Inside diameter (inches) 121,063.8 :T1/DUMP 2nd critical (steel):

150 for? W 156 103 :Tx/6.3613 (DH-d2) 393,457.2 :TV Dufdz For beryllium mandrels L, 039.7328 (Dura) 4 2nd critical (beryllium):

Ratio of 1st critical beryllium to steel:

302,753.3 fB TV DLH From the foregoing, it will be seen that the first critical frequency occurs substantially higher in the inventive mandrel than those constructed according to the prior artthereby allowing considerably higher speeds during reeling without danger of machine breakdown.

While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

We claim:

y1. A mandrel for high-speed reeling and the like comprising an elongated body having at least the major portion of the length thereof constructed of a material having a modulus of elasticity-density ratio in excess of about 2X108 inches, and means for supporting said body in reeling means.

2. The structure of claim 1 in which said supporting means includes at least one end portion of said body integral with the body remainder and constructed of a material different from the first-mentioned material.

3. The structure of claim 1 in which said material is beryllium.

4. The structure of claim 1 in which said supporting means includes end portions constructed of ferrous material, one end portion including means for immobilizing a core relative to said body.

= 2.5000 TIMES References Cited UNITED STATES PATENTS 697,776 4/ 1902 Barker 242-685 NATHAN L. MINTZ, Primary Examiner 

